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:''For a list of keyboard shortcuts, see Table of keyboard shortcuts'' or The Alt key (pronounced ) on a computer keyboard is used to change (alternate) the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer will perform an function, which varies from program to program. The international standard ISO/IEC 9995-2 calls it ''Alternate key''. The key is located either side of the Space bar, but in non-US PC keyboard layouts, rather than a second Alt key, there is an 'Alt Gr' key to the right of the space bar. Both placements are in accordance with ISO/IEC 9995-2. The standardized keyboard symbol for the Alt key (which may be used when the usual Latin lettering “Alt” is not preferred for labelling the key) is given in ISO/IEC 9995-7 as symbol 25, and in ISO 7000 ''“Graphical symbols for use on equipment”'' as symbol ISO-7000-2105. This symbol is encoded in Unicode as U+2387 (⎇). The Alt key should not be confused with the Altmode key (sometimes also labelled Alt) on some Teletype and ASCII terminals, which is a synonym for the ASCII escape character. ==Evolution== The Alt key has come to replace the Meta key of the old MIT keyboards. In their original function, both Alt and Meta would set the high bit of the signal generated by the key to 1 (for example, A generates 01000001 while generates 11000001). However, in modern software, due to the requirement of the high bit for internationalisation, Alt no longer works in such a way. Since the 1990s Alt has been printed on the Option key on most Mac keyboards. Alt is used in non-Mac software, such as Unix and Windows programs, but in OS X it is always referred as Option key. Option key's behaviour in Mac OS X differs slightly from that of the Windows Alt key (it is used as a modifier rather than to access pull-down menus, for example). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「alt key」の詳細全文を読む スポンサード リンク
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